1. Field of the Invention
This invention relates in general to automatic liquid dispensers which are capable of sensing the size of a cup which is placed on the machine and which automatically fills either a small, medium or a large cup without operation or attendance by the operator.
2. Description of the Prior Art
Prior art automatic dispensers have used oscillators which were moisture sensitive and such oscillators have failed due to burn out as, for example, by failure of the current limiting resistor. Also, in the prior art dispensers, if a cup was quickly changed a short cup would result rather than being completely filled. Also, in systems of the prior art, sources such as the sun have tended to swamp the infra-red sensing systems so as to prevent pulses from passing through the sensor.